The human temporomandibular joint is a rather complex joint that must function in a coordinated way if troublesome derangements are to be avoided. Situated just in front of the ear, it consists of a condyle at the upper end of the mandible that fits into the condylar fossa on the lower part of the temporal bone of the skull, and a meniscus (articular disk) interposed between the condyle and the articulating surface of the temporal bone. The mandible, the large heavy bone of the lower jaw, is shaped rather like a horseshoe and pivots about the articulating disk in a gliding, hinge like motion.
The temporomandibular joint is susceptible to a variety of problems, some of which may be corrected by exercise therapy, and others which may require surgical techniques. The latter course of treatment gives rise to the need for post-surgical manipulation in order to preserve or enhance operation of the joint. In the past, therapeutic treatment of the temporomandibular joint by flexing the joint has been primarily provided by manual flexure of the joint performed by a nurse, physical therapist, or by exercise done by the patient.
Generally in medical treatment, there have been developed a variety of devices which may be utilized to some limited extent to induce motion in a human joint. With respect to joints other than the temporomandibular joint, a number of such devices are known. In the patent literature, U.S. Pat. No. 4,487,199 issued Dec. 11, 1984 to Saringer for DEVICE FOR IMPARTING CONTINUOUS MOTION TO HUMAN JOINTS, and U.S. Pat. No. 4,716,889 issued Jan. 5, 1988 to Saringer, with the same title, are the closest art of which I am aware. Other patents of which I am aware include devices for imparting motion to joints include U.S. Pat. No. 2,832,334 issued Apr. 29, 1958 to Whitelaw for THERAPEUTIC DEVICE FOR USE IN MANIPULATIVE TREATMENT OF JOINTS OF THE HUMAN BODY; U.S. Pat. No. 3,683,897 issued Aug. 15, 1972 to Shield et al for APPARATUS FOR MOVING OR ACTIVATING PARTS OF THE BODY; U.S. Pat. No. 3,976,057 issued Aug. 24, 1976 to Barclay for JOINT FLEXING APPARATUS; and French Patent No. 70.37360 to Cabinet Malemont for APPAREIL DE MOBILISATION CONTINUE DES DOIGTS POUR PREVENIIR LES ANKYLOSES CONSECUTIVES AUX TROUBLES TROPHIQUES POST-TRAMATIQUES OU INFECTIEUX.
For the most part, the patent documents identified in the preceeding paragraph disclose devices which include only linear motion, or accommodate pivotal motion via means which are unsuited for adaptation to the temporomandibular joint.
The closest prior art device for exercises of the temporomandibular joint of which I am aware is a device known as the "Mobilimb J1--TMJ CPM," sold by Toronto Medical Corporation of Canada. The Mobilimb device is comprised of an actuation portion which includes a battery powered mechanical drive unit to provide an adjustable range of reciprocating linear motion, and a pair of dental mold attachment portions which are adapted to fit dental impression molds. However, the Mobilimb J1 device as presently utilized includes dental mold attachment portions which fail to accommodate the fact that the front portion of a human mandible moves in an arc, rather than merely vertically, when the jaw is opened. Thus, the Mobilimb device, due to the defects in the dental mold attachment portions as have been developed and used heretofore, fails to track the actual pattern of movement of a human mandible.
Unlike the actual movement of a human jaw, which traverses an arc from the pivot point of the temporomandibular joint, the presently used dental mold attachment portions of the Mobilimb J1 device provide only vertical motion, as will be further described hereinbelow. Thus, the present attachments to the device are deficient in that they fail to provide for the simultaneous forward to rearward movement and the pivotal, curvelinear motion of the bottom of a jaw as it is opened. Thus, there exists a continuing need in the art for an improved method of providing an exercise device for the temporomandibular joint which provides motion which corresponds to the natural movement of the jaw as it is opened and closed.